Alkaline anion-exchange membranes (AAEMs) for solid alkaline fuel cells (SAFC) application were successfully prepared by radiation induced grafting of Vinyl benzyl chloride onto ultra-high molecular ...weight polyethylene powder (UHMWPE), followed by film fabrication by melt pressing and quaternization with a Guanidine derivative, 1,1,3,3-tetramethyl-2-n-butylguanidine (TMBG). The chemical structures of the resulting AAEMs were examined by Fourier transform infrared, which showed that the grafted membranes were successfully functionalized by modified guanidine. The performance of the AEMs, including ion exchange capacity, water uptake, in-plane swelling, methanol uptake, methanol permeability, and hydroxide ion conductivity were investigated. Thermal analysis showed that the Guanidine-based AAEMs comprises better thermal stability. The AAEMs membrane exhibited a maximum ionic conductivity of 27.7 mS cm−1 at 90 °C. Methanol permeability is found to be in the order of 10−9 cm2 s−1, which is significantly lower than that of Nafion®. The membranes have useful properties as an anion exchange membranes suitable for alkaline fuel cells.
•Polyethylene-based AEMs (Mi-GOH), containing guanidine pendant groups, were prepared by radiation induced grafted technique.•Grafting was performed onto powder polymer substrate.•Membrane fabrication from grafted powder was better practice than membrane grafting.•Guanidine functionalized AEMs are found to exhibit good thermal stability.•The maximum hydroxide conductivity of AEM was found to be 27.7 mS cm−1 at 90 °C while methanol permeability was in the order of 10−9 cm2 s−1.
In this paper, we determined an effective substitution of Ge at Sb sites in Nd-filled p-type skutterudites, a series of Nd.9Fe2Co2Sb12-xGex compounds with compositions of x = 0, 0.1, 0.2, 0.3 and 0.4 ...were synthesized by home-made induction melting, assembled inside the glove box and followed by spark plasma sintering process (SPS). The thermoelectric properties are investigated as a function of Ge doping content with fixed Nd-filler at 0.9 and the formation of skutterudite phase is characterized by X-ray diffraction. All samples possess positive Seebeck coefficients, representing effective p-type doping. It is observed that the electrical conductivity decreases with decreasing Ge doping concentrations while increased with temperature due to bipolar effect. The lightly doped samples (x = 0.1 and 0.2) have lower lattice thermal conductivity over the entire temperature range, in which x = 0.2 sample shows the highest ZT value of 0.82 at 700 K, which is 30% higher than that of the Ge-free sample. The improvement in ZT can be attributed to the optimized carrier concentration and reduced thermal conductivity. The enhancement of ZT through Ge doping, coupled with drastically reduced processing time, shows that these compounds may have great potential in application as p-type segments of the thermoelectric devices.
Being located in the Sun Belt, Pakistan is rich in sunlight and receives a high mean irradiation. This condition is ideal for harnessing Sun’s power for solar energy applications by using solar ...reflectors. In spite of possessing such a rich solar irradiation area, Pakistan is facing energy crisis because most of the energy resources are still unexploited. This paper discusses the energy crisis of Pakistan and provides the solution by putting efforts into solar energy technology, as well as devising innovative ways to incorporate solar reflectors into a solar panel and get more power generation out of it by a diminutive modification. Reflectors are used in the solar technology to concentrate the sunlight onto the solar panels. They employ glass as a base material with a silver coating and a protective layer over it. They elevate the energy input of solar panels as the whole solar spectrum is reflected on them. Materials with more reflective properties are needed to be used to increase the reflectivity and efficiency of solar reflectors. In Pakistan, no significant work is done till now towards the development of solar reflectors. If solar reflectors are used with the solar panels, then their efficiency as well as production from the solar panels will be maximized.
The purpose of this study is to develop new oxide ionic conductors based on nanocomposite materials for an advanced fuel cell (NANOCOFC) approach. The novel two phase nanocomposite oxide ionic ...conductors, Ce
0.8Sm
0.2O
2
−
δ
(SDC)-Y
2O
3 were synthesized by a co-precipitation method. The structure and morphology of the prepared electrolyte were investigated by means of X-ray diffraction (XRD) and high resolution scanning electron microscopy (HRSEM). XRD results showed a two phase composite consisting of yttrium oxide and samaria doped ceria and SEM results exhibited a nanostructure form of the sample. The yttrium oxide was used on the SDC as a second phase. The interface between two constituent phases and the ionic conductivities were studied with electrochemical impedance spectroscopy (EIS). An electrochemical study showed high oxide ion mobility and conductivity of the Y
2O
3-SDC two phase nanocomposite electrolytes at a low temperature (300–600
°C). Maximum conductivity (about 1.0
S
cm
−1) was obtained for the optimized Y
2O
3-SDC composite electrolyte at 600
°C. It is found that the nanocomposite electrolytes show higher conductivities with the increased concentration of yttrium oxides but decreases after reaching a certain level. A high fuel cell performance, 0.75
W
cm
−2, was achieved at 580
°C.
► The novel two phase nanocomposite oxide ionic conductors, Ce
0.8Sm
0.2O
2−δ (SDC)-Y
2O
3. ► Maximum conductivity (about 1.0 S cm
−1) was obtained for the optimized Y
2O
3- SDC composite electrolyte at 600 °C. ► A high fuel cell performance, 0.75Wcm
−2, was achieved at 580 °C. ► A new oxide ionic conductors based on nanocomposite materials for advanced fuel cell.
Nanocomposites Samarium doped Ceria (SDC), Gadolinium doped Ceria (GDC), core shell SDC amorphous Na2CO3 (SDCC) and GDC amorphous Na2CO3 (GDCC) were synthesized using co-precipitation method and then ...compared to obtain better solid oxide electrolytes materials for low temperature Solid Oxide Fuel Cell (SOFCs). The comparison is done in terms of structure, crystallanity, thermal stability, conductivity and cell performance. In present work, XRD analysis confirmed proper doping of Sm and Gd in both single phase (SDC, GDC) and dual phase core shell (SDCC, GDCC) electrolyte materials. EDX analysis validated the presence of Sm and Gd in both single and dual phase electrolyte materials; also confirming the presence of amorphous Na2CO3 in SDCC and GDCC. From TGA analysis a steep weight loss is observed in case of SDCC and GDCC when temperature rises above 725 °C while SDC and GDC do not show any loss. The ionic conductivity and cell performance of single phase SDC and GDC nanocomposite were compared with core shell GDC/amorphous Na2CO3 and SDC/ amorphous Na2CO3 nanocomposites using methane fuel. It is observed that dual phase core shell electrolytes materials (SDCC, GDCC) show better performance in low temperature range than their corresponding single phase electrolyte materials (SDC, GDC) with methane fuel.
We developed a new nickel-free anode for a low-temperature solid oxide fuel cell (LTSOFC) that demonstrated an outstanding electrochemical output of 1000
mW
cm
−2 at 550
°C. The nanostructure anode ...had good conductivity and was compatible with cerium oxide-based electrolytes. The performance of a single cell was comparable and or better than those using standard Ni-YSZ and Ni-SDC electrodes (anode). It may have applications for hydrocarbon-based fuel for preventing carbon deposition and replacing nickel in the anode of LTSOFCs.
Mixed metallic oxides are getting increasing attention as novel electrode materials for energy conversion devices. However, low mixed ionic-electronic conductivity and high operating temperature ...hamper the practical applications of these devices. This study reports an effective strategy to improve the conductivity and performance of the fuel cell at low temperature by partially incorporating graphene in the Li0.1Cu0.2Zn0.7-oxide (LCZ) composite. The proposed cathode material is synthesized via the cost effective conventional solid-state route. Graphene incorporated LCZ shows excellent performance, which is attributed to the favorable charge transport paths offering low area-specific resistance. An X-ray diffractometer (XRD) and scanning electron microscope (SEM) are employed for microstructural and surface morphological analyses, respectively. Electrical conductivities of all the materials are determined by the DC four probe method, and interestingly, LCZ-1.5% graphene exhibits an excellent conductivity of 3.5 S/cm in air atmosphere at a temperature of 450 °C with a minimum value of 0.057 Ωcm2 area-specific resistance (ASR) that demonstrates significantly good performance. Moreover, the three-layer fuel cell device is fabricated using sodium carbonated Sm0.2Ce0.8O (NSDC) as an electrolyte, which can operate at low temperatures exhibiting open circuit voltage 0.95 V and shows a peak power density, i.e., 267.5 mW/cm2 with hydrogen as the fuel.
Sm0.2Ce0.8O1.9 (SDC)/Na2CO3 nanocomposite synthesized by the co-precipitation process has been investigated for the potential electrolyte application in low-temperature solid oxide fuel cells ...(SOFCs). The conduction mechanism of the SDC/Na2CO3 nanocomposite has been studied. The performance of 20 mW cm−2 at 490 °C for fuel cell using Na2CO3 as electrolyte has been obtained and the proton conduction mechanism has been proposed. This communication demonstrates the feasibility of direct utilization of methanol in low-temperature SOFCs with the SDC/Na2CO3 nanocomposite electrolyte. A fairly high peak power density of 512 mW cm−2 at 550 °C for fuel cell fueled by methanol has been achieved. Thermodynamical equilibrium composition for the mixture of steam/methanol has been calculated, and no presence of C is predicted over the entire temperature range. The long-term stability test of open circuit voltage (OCV) indicates the SDC/Na2CO3 nanocomposite electrolyte can keep stable and no visual carbon deposition has been observed over the anode surface.
In this study, nickel oxide–Y2O3-doped ZrO2 (NiO-YSZ) composite powder as an anode material was synthesized using a cost-effective combustion method for high-temperature solid oxide fuel cell (SOFC). ...Further, the effects of sintering temperatures (1200, 1300, and 1400 °C) were studied for its properties in relation to the SOFC performance. The prepared and sintered NiO-YSZ materials were characterized for their surface morphology, composition, structure, and conductivity. The cubic crystalline nature of NiO and YSZ was sufficed by X-ray diffraction, and SEM images revealed an increase in the densification of microstructure by an increase in the sintering temperature. EDX spectrum confirmed the presence of nickel, yttrium, and zirconia without any impurity. Conductivity measurements, under a hydrogen environment, revealed that NiO-YSZ, sintered at 1400 °C, exhibits better conductivity compared to the samples sintered at lower temperatures. Electrochemical performance of button-cells was also evaluated and peak power density of 0.62 Wcm−2 is observed at 800 °C. The citrate combustion method provided peak performance for cells containing anode sintered at 1200 °C, which was previously reported at higher sintering temperatures. Therefore, the citrate combustion method is found to be a suitable route to synthesize NiO-YSZ at low sintering temperature.
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•This review provides a summary of recent development of single component SOFCs.•Criteria of materials selection for the single component SOFCs have been discussed.•The descriptions ...on charge separation mechanism at particle level are reviewed.•This review includes studies on built-in electric fields of junctions.•The junction effect on electronic and ionic transport is reviewed.
Despite the high capabilities to replace combustion systems and produce sustainable energy, solid oxide fuel cells (SOFCs) still have not yet been successfully commercialized. In this context, single component SOFC has been developed as a new oriented fuel cell R&D strategy in the past decades, providing great promise to commercialization. This paper presents a mini review on recent studies with respect to the development of the state-of-the-art single component SOFC to overcome the constraints of high operating temperatures. Different from conventional three-component SOFC, the single component SOFC is featured of containing a homogeneous layer with hybrid dual ions (O2–/H+) conduction based on semiconductor-ion hetero-structure materials. The Schottky or p-n junction built-in electric field evidence the cell operation even at low-temperature up to (300–600 °C), which brings a new overwhelming framework for research and development of fuel cell. The functionality of the single component is principally determined by the interface kinetics, which has dimensions of super-fast (hybrid) ionic transport. Therefore, innovative design of semiconducting-ionic materials is systematically reviewed in terms of inter-facial properties/mechanisms, and transition from non-functional to functional materials with potential of dual ions conduction. Further, it is followed by weighted the potential of this new device as compared with conventional SOFCs. Finally, the future framework, advancement, and bright perspectives of this innovative device have been discussed.
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